The field of art to which the claimed invention pertains is chlorinated aromatic hydrocarbon separation. More specifically, the claimed invention relates to the separation of ortho chlorotoluene and ortho-dichlorobenzene from their meta and para isomers by use of a specific crystalline aluminophosphate adsorbent which selectively removes the above ortho aromatic isomers. The selectively adsorbed ortho aromatic isomers are removed from the adsorbent through a desorption step.